This is an interdisciplinary and interinstitutional project proposed by Dr. Van C. Mow, Rensselaer Polytechnic Institute, and Dr. David R. Eyre, Children's Hospital Medical Center, Harvard Medical School, to continue their earlier cooperative research efforts. The RPI group will continue to study all of the biomechanical and mechanochemical properties of articular cartilage and the CHMC group will continue to pursue all biochemical characterizations and modifications of normal and osteoarthritic animal tissues. RPI will be the primary grantee institution and CHMC will subcontract from RPI. In this continuation project, we seek to further determine the correlation between the biochemical composition and structural changes of articular cartilage specimens and their biomechanical and mechanochemical properties. In so doing, we would have determined: (1) the appropriate intrinsic material moduli for the cartilage matrix, (2) the permeability coefficients, and (3) various matrix mechanochemical transduction coefficients. All these properties will be statistically correlated to the biochemical composition of normal tissue: (1) water content, (2) collagen content and type, (3) uronic acid content, and (4) glycosaminoglycan content and type; and specific biochemical alterations of matrix macromolecule conformations: (1) proteoglycan extraction, (2) cross-linking, and (3) enzymatic digestions. From these experimental data, we hope to develop an understanding of matrix macromolecular interactions for normal and biochemically treated tissues. In summary, the aim of this proposed research is to develop a quantitative molecular and structural model for normal articular cartilage mechanical and mechanochemical properties.